21/02/2025
Knee flexion contracture (KFC) is a condition that causes the knee to bend too much, limiting mobility and increasing the risk of disability. It can occur due to a number of reasons, including osteoarthritis, rheumatoid arthritis, or after knee surgery. A flexion deformity of the knee is the inability to fully straighten or extend the knee, also known as flexion contracture. Normal active range of motion (AROM) of the knee is 0° extension and 140° flexion.
Symptoms
Crouch gait
Difficulty standing, reaching, and walking
Pain in the front of the thigh and knee
Causes
Deformities of the bone, ligament, or joint capsule
Cerebral palsy
Congenital deformities
Post-traumatic deformities
Total knee replacement
Treatment
Surgery to release contracted soft tissues and correct the bone
Rehabilitation to maintain full extension
Conditions such as rheumatoid arthritis and osteoarthritis lead to joint destruction that can result in flexion deformities.
Neuromuscular conditions like cerebral palsy may cause spasticity in the hamstrings, contributing to knee flexion.
Injuries to the hip or ankle joints can also affect knee mechanics and lead to contractures.
Other degenerative conditions such as osteogenesis imperfecta or pterygium syndrome may predispose individuals to this deformity.